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Title: Refinement of the Pt(111)+c(4x2)-2CO structure using automatedtensor LEED

Journal Article · · Surface Review and Letters
OSTI ID:894397

The structure of Pt(111)+c(4x2)-2CO has been refined usingthe powerful capabilities of automated tensor LEED, in particular todetermine hitherto unexplored adsorbate-induced relaxations in thesubstrate. The refinement considerably improves the fit to experimentobtained in a previous structural analysis performed with low-energyelectron diffraction (LEED). This study confirms that CO occupies bothtop and bridge sites. It finds a buckling of the outermost Pt layer, suchthat the Pt atoms bonded to CO molecules are raised out of the surface by0.06(plus/minus)0.04 Angstrom relative to the Pt atoms which do not bondto CO. The raised atoms have a spacing of 2.28(plus/minus)0.04 Angstromto the next Pt layer, expanded from the bulk spacing of 2.2655 Angstrom,while the depressed Pt atoms have a reduced spacing of2.22(plus/minus)0.04 Angstrom to the next Pt layer. The second Pt layeritself shows minor buckling of 0.03(plus/minus)0.04 Angstrom. No lateralrelaxations in the substrate are detected within 0.1 Angstrom. The COmolecules are perpendicular to the surface, with bond lengths of1.12(plus/minus)0.04 Angstrom and 1.19(plus/minus)0.04 Angstrom in topand bridge sites, respectively. The C-Pd spacings, measured betweenbonding atoms, are 1.92(plus/minus)0.04 Angstrom and 1.4(plus/minus)0.04Angstrom in top and bridge sites, respectively.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Director, Office of Science. Office of Basic EnergySciences. Division of Materials Sciences
DOE Contract Number:
DE-AC02-05CH11231
OSTI ID:
894397
Report Number(s):
LBNL-44369; R&D Project: 517801
Journal Information:
Surface Review and Letters, Vol. 7, Issue 1-2; Related Information: Journal Publication Date: Feb.-Apr.2000
Country of Publication:
United States
Language:
English